Treating hides, skins, leather or the like



Patented Man/6, 1934 TREATING HIDES,

SKINS, LEATHER OR THE LIKE Karl Brodersen, Dessau in Anhait, and Heinrich Wagner, Mannheim, Germany, assignors to I. G;

Farbenindustrie Aktiengesellschaft,

Frankforton-the-Main, Germany No Drawing. Application April 30, 1932, Serial No. 608,556. In Germany-May 6,1931

The present invention relates to a process of improving hides, skins, leather orthe like.

According to this invention, hides, skins, leather and furs can be caused to assume a particular softness and suppleness in conjunction with an excellent compact feel, by treating them with mono-esters of polyhydric alcohols and acids the alkali salts of which assume the character of soaps, orof derivatives thereof. Substances primarily suitable for the purpose of the present invention are certain carboxylic esters such as, for example, the mono-lauric acid ester, stearic acid ester or oleic acid ester, of glycol, glycerin, erythrite, sorbite, and poly-glycerins or other polyhydric alcohols. Derivatives of such compounds such as, for example, their inorganic esters such as the sulfuric ester, phosphoric ester, and the like, and also mixtures of various of the esters hereinbefore mentioned, are also suitable.

Treatment with the hereinbefore mentioned substances yields vivid tints on dyed furs that are faster to rubbing and also yields more vivid and brighter leather. Sealconey and nutria skins which become too soft during the dyeing process regain their original soft form and their compact feel.-

The skins or the like are either treated in a separate bath with the aqueous solutions of the esters or are treated with the emulsions thereof prepared in known manner. Another mode of carrying out the process of the present invention consists in adding these esters to a treating bath, for example, to the dye bath. Moreover, the wood shavings which serve for finishing the skins may be impregnated with the solutions or emulsions of the esters; it is, of course, also possible to employ other inorganic or organic compounds, customary in 'the dressing of skins. A special advantage of the improving process of the present invention consists in thatthe hair of the firs obtains a lustre very that of 7 living hair.

The monocarboxylic acid esters of the polyglycerins employed in the process of the present invention may, for instance, be obtained by heating two molecular proportions at least of similar or dissimilar polyhvdric alcohols, in the presence of small quantities of an agent having an alkaline action, with one molecular proportion of a carboxylic acid.

The following examples serve to illustrative the invention, the parts being by weight:

Example 1.15 liters of hot water are poured over 1.2 k s. of a mono-ester obtained by heating 235 parts of coconut oil and 740 parts of glycerin in the presence of 3 parts of potash soap to 240 0., raising this temperature to 270 C.'to 280 C. in the course of 3 hours and maintaining it for some hours at this level. 10 kgs. of sand and 30 kgs. of sieved hard-wood shavings are well mixed with the aqueous solution obtained in order uniformly to moisten same. The mixture is employed for clearing about 30 kgs. of dry, colored skin material while maintaining it for some hours in a moist state in the purification drum. The skinmaterial is taken out of the drum, dried and then further treated in the usual manner.

Example 2.-100 kgs. of sieved hard-wood shavings are uniformly moistened with a solution of-5 kgs. in 20 liters of hot water of the product described in Example 1; the shavings are then dried and the dry, colored fur material is cleared therewith for several hours.

Example 3.The hair tips of the colored and dried furs are brushed with a solution of 1 kg. in 20 liters of hot water, of the product described in Example 1. The furs are then dried and cleared as usual.

Example 4.Colored furs are treated in the paddle at a temperature of 25 C. for 15 to 20 minutes in a bath containing 5 to 8 grams per liter of the mono-ester described in Example 1, The fur obtained has a coloration that is faster to rubbing and more vivid, and leather thus treated is softer and brighter. v

Example 5.Furs that have become too soft in the dyeing process, such as sealco'ney or nutria skins are treated in the usual manner in the machine for finishing them. Then a solution containing 50 grams per liter of the mono-ester described in Example 1 and 50 grams of magnesium chloride is brushed on the top hair of the fur. In this manner a perfectly satisfactory soft and supple fur is obtained having an excellent and compact feel.

Instead of using the product obtainable from coconut oil and glycerin, as employed in the, foregoing examples, there may be employed with the same success mono-esters composed of the fatty acids of olive oil, castor oil, earthnut oil, rape oil, tallow or other animal or vegetable fats or naphthenic acid, resin acids, acids as obtainable by oxidation of the higher paraflin hydrocarbons on the one hand and polyhydric alcohols, such as glycol, polyglycol, glycerin, polyglycerin, sorbite, manni'te and the like on the other hand. These mono-esters are obtainable, for instance, as mentioned above, by heating the oils, such as coconut oil, castor oil, olive oil, linseed oil, earthnut oil, with the said polyhydric alcohols or mixtures thereof in the presence of a small percentage of a soap or a caustic lye, or by esterification 01' the free acids, such as oleic acid, resin acids, naphthenic acids, with an excess of the polyhydric alcohol. Alternatively, other esters of the said acids, such as palmitic acid ethylester, lauric acid methylester'may be subjected to alcoholysis with a polyhydric alcohol.

The raw products obtainable according to these processes are suitable for the purpose set forth without further isolation of the mono-esters formed. It is obvious that under certain conditions, especially when preparing the esters of polyhydric alcohols containing a great number of free OH-groups, such as sorbite and polyglycerins, esters may be formed which, it is true, contain still free OH-groups, in which, however,

more than one OH-group is esterifled. These products are likewise suitable, if such a number of free OH-groups is present in the molecule that the product is easily distributable in water.

Instead of the said esters of acids the alkali salts of which show the character of soaps with .polyhydric alcohols for the purpose set forth,

such derivatives may be used in which one or several free hydroxyl groups of the polyhydric alcohol are esterified with sulfuric acid or phosphoric acid.

What we claim is: 1. The process which comprises treating hides,

furs, skins, leather or the like with an ester of a polyhydric aliphatic alcohol and of an organic acid, the alkali salts of said acid assuming the character of soaps, said ester containing free- OH-groups in the alcoholic radicle.

2. The process which comprises treating hides; furs, skins, leather or the like with a-mono-ester of a polyhydric aliphatic alcohol and of an organic acid, the alkali salts of said acid assuming the character of soaps.

3. The process which comprises treating hides, furs, leather or the like with a mono ester of glycerin or polyglyc'erln and of an organic. acid, the alkali salts of said acid assuming the character of soaps.

4 The process which comprises treating hides, furs, skins, leather or the like with a mono-ester of glycerin or polyglycerin and of a higher fa acid with more than 10 carbon atoms.

5. The process which comprises treating hides, fm's, skins, leather or the like with a mono-ester of glycerin or polyglycerin and of the fatty acid of coconut oil'.' V

6. The process which comprises treating hides,

furs, skins, leather or the like with the reaction product obtainable by heating coconut oil with about threefold its weight of glycerin in the pres ence of an alkaline substance.

' KARL BRODIRSEN.

HEINRICH WAGNER. 

